That was very useful - thanks! Confirms what I suspected when I prospect in Cornwall and Devon in the UK. Past history from tin miners in the 1800s-1940s. I find lots of man-made dams, side channels, and even a slime pit!
Brilliant video, very informative ! Thanks for making these, I have become hugely interested and passionate about prospecting and gem fossicking over the last few years, your vids are very useful and professionaly done. Thanks mate 👍
Here in the western US I"ve seen a lot of alluvial workings over the years. The only ones that weren't gold related (we don't have alluvial tin in the west US) were for, oddly enough, blue agate. Found near Ellensburg, WA, the ridiculously valuable blue agate is known as Ellensburg blue.
Typically pit fields are for digging through perlite to extract geodes in domes, hogsbacks, and other dyke structures. Other pit fields are for the digging through ash and tuff for petrified wood. The Ellensburg digs would be through basalt to extract amygdules.
There is a chapter in Ion Idriess book 'prospecting for gold' on wet season claims where he mentions the technique of mounding up the paydirt on a platform above the dry creek bed or on some fallen trees and branches, and when the rain fell it would be sluiced down the creek
@@GeologyUpSkill when I was a kid, my dad would keep his books in my bedroom, I started reading that when I was about 12. That and the prospectors guide fir NSW from the 1960s, needless to say I became a geologist.
Was placer activity associated with explosives? I having a hard time thinking about getting thru tree stumps and roots, even with modern carbide faced machinery. Were placer deposits serviced by roads or were they narrow and unrefined like modern hiking trails? Shaded relief on a GIS app can reveal quite a few roads in my area. I'm thinking that most of it was after 1880 and before WWII, but people have been mining here since the 17th Century. Did they have a secondary goal of providing lumber for construction, or was that left to a separate industry?
Most of the historical placer work was done without explosives and with a minimum of infrastructure, although I have seen some where long contour channels were cut to bring water from higher elevation to run sluicing operations.
Excellent-i just subscribed-you seem to know your stuff- i found contour trenches near Sofala NSw and was wondering what they were-you have cleared that up for me- TY
In areas of more available water, old timers here in California would ground sluice. Storing water up and turning it on the ground they wanted to sluice. Kinda like hydralicking the ground but without the force of a nozzle and using just the erosive forces of water across a flat surface.
Another marker that I would see occasionally in Malaysia where the Touraine was quite mountainous and you would find lots of waterfalls were channels leading from the tops of the waterfalls to areas that at first glance just seemed like they were covered in fern or smaller shrubbery Which onece was burnt away would usually contain softer oxidised rocks in zones that had been dug out. even entire hillsides could be hidden in such a manner and it was always useful to check for channels perpendicular to the hillside on each side of the oxidised zones Which had undergone ancient mining as on occasion Small tracks following the same topography would occasionally lead you to other sites further away, I believe the furthest one I found was around 200 m. I also recall seeing large round boulder that resembled retaining walls on the outside of corners Mostly on narrow rivers with steep banks that looks like they may have even been to metres tall which I always used wondered whether they were there to Fortify the external corners in some of these narrow rivers Or prevent erosion and mudslides as the rocks looked out of place in the area’s. Have you come across ancient formations such as the ones I’ve described?
Yes. I saw something very similar in Indonesia. A small race cut to divert a small river around a waterfall (presumably to allow the alluvium in the plunge pool to be extracted). Judging by the size of trees in the diversion channel, it was several hundred years old!
You can get a rough idea by estimating the volume of each dump in cubic metres and multiplying by 2. Most historical alluvial shafts that I have seen in good condition are about 1m x 0.5m in plan so they would generate about 1 cubic metre of mullock for every 2m down. It's a pretty rough estimate, but saves a lot of digging!
Yes, dowsing with the modern light weight ball bearing dowsing rod while using physics will accurately decipher all edges, exact center, depth buried and angle of deposition, and most important GRADING. Read the book The Art of Dowsing - Separating Science from Superstition for learning all the physics involved and how to use it in dowsing.
Good One Mr Nick, in Laos, we just follow the Vietnamese Excavators to the aluvial pits? No problem> One suggestion on your Video Production> More Dirt Bikes, please :)
That was very useful - thanks! Confirms what I suspected when I prospect in Cornwall and Devon in the UK. Past history from tin miners in the 1800s-1940s. I find lots of man-made dams, side channels, and even a slime pit!
Most of the workings in this video are for gold, but exactly the same techniques were used for alluvial tin.
Like us all thank you for what you do for me you're my personal teacher,I still have alot to learn about my lode claim in Colorado
Thanks. Glad you found the videos useful.
Brilliant video, very informative ! Thanks for making these, I have become hugely interested and passionate about prospecting and gem fossicking over the last few years, your vids are very useful and professionaly done. Thanks mate 👍
Glad you found it useful. Hope it helps you to find some gold!
@@GeologyUpSkill thanks mate 👍
Great info thanks!
Thanks. Hope it helps you find some.
Here in the western US I"ve seen a lot of alluvial workings over the years. The only ones that weren't gold related (we don't have alluvial tin in the west US) were for, oddly enough, blue agate. Found near Ellensburg, WA, the ridiculously valuable blue agate is known as Ellensburg blue.
Similar story here with opals. Add a bit of blue colour and the value goes up!
Typically pit fields are for digging through perlite to extract geodes in domes, hogsbacks, and other dyke structures. Other pit fields are for the digging through ash and tuff for petrified wood. The Ellensburg digs would be through basalt to extract amygdules.
Where i live in the US we also have to look for hydraulically mined alluvium on hillsides.
Good point I will have to find one of those and put it in the extended version.
WOW! This is both interesting and helpful!
I agree. Alluvial workings are very interesting and helpful.
Great video! Please share more of your knowledge about old alluvial workings in future clips. 😊
Thanks Aleks. My most recent outcrop of the day video adds a little to this story. ua-cam.com/video/_XG8_N7eo6I/v-deo.html
J’adore vos vidéos ! Merci bien d’avoir partagé vos savoir-faire
Merci beaucoup. Content que ça t'aide !
Thankyou for the video , and sharing your good helpfull information .
Thanks for taking the time to comment. Glad you found it useful.
Thanks mate great vid Hope to see you out there one day !
Thanks. Following alluvials is my favourite passtime as you can see!
Great video full of knowledge, thanks for sharing 👍
Thanks. Hope it helps you to find something :)
@GeologyUpSkill definitely does help, I certainly learned something that will improve my prospects 🫡
There is a chapter in Ion Idriess book 'prospecting for gold' on wet season claims where he mentions the technique of mounding up the paydirt on a platform above the dry creek bed or on some fallen trees and branches, and when the rain fell it would be sluiced down the creek
That book was my bible as a young geologist!
@@GeologyUpSkill when I was a kid, my dad would keep his books in my bedroom, I started reading that when I was about 12. That and the prospectors guide fir NSW from the 1960s, needless to say I became a geologist.
Was placer activity associated with explosives? I having a hard time thinking about getting thru tree stumps and roots, even with modern carbide faced machinery.
Were placer deposits serviced by roads or were they narrow and unrefined like modern hiking trails? Shaded relief on a GIS app can reveal quite a few roads in my area. I'm thinking that most of it was after 1880 and before WWII, but people have been mining here since the 17th Century. Did they have a secondary goal of providing lumber for construction, or was that left to a separate industry?
Most of the historical placer work was done without explosives and with a minimum of infrastructure, although I have seen some where long contour channels were cut to bring water from higher elevation to run sluicing operations.
Excellent-i just subscribed-you seem to know your stuff- i found contour trenches near Sofala NSw and was wondering what they were-you have cleared that up for me- TY
Yes. I have seen some very extensive contour trences for sluicing around Orange in NSW.
theres alot of good knowledge in this one, thank you! subscribed
Thanks. Hope it helps you to find some gold.
In areas of more available water, old timers here in California would ground sluice. Storing water up and turning it on the ground they wanted to sluice. Kinda like hydralicking the ground but without the force of a nozzle and using just the erosive forces of water across a flat surface.
A little of that here in Australia, particularly for tin in north Queensland.
It doesn’t matter how remote I am, some bugger with a mule and a gold pan has been there before.
Yes, but fortunately everyone sees a place with new eyes.
Really Good video Nick
Thanks Russell.
Another marker that I would see occasionally in Malaysia where the Touraine was quite mountainous and you would find lots of waterfalls were channels leading from the tops of the waterfalls to areas that at first glance just seemed like they were covered in fern or smaller shrubbery Which onece was burnt away would usually contain softer oxidised rocks in zones that had been dug out. even entire hillsides could be hidden in such a manner and it was always useful to check for channels perpendicular to the hillside on each side of the oxidised zones Which had undergone ancient mining as on occasion Small tracks following the same topography would occasionally lead you to other sites further away, I believe the furthest one I found was around 200 m.
I also recall seeing large round boulder that resembled retaining walls on the outside of corners Mostly on narrow rivers with steep banks that looks like they may have even been to metres tall which I always used wondered whether they were there to Fortify the external corners in some of these narrow rivers Or prevent erosion and mudslides as the rocks looked out of place in the area’s. Have you come across ancient formations such as the ones I’ve described?
Yes. I saw something very similar in Indonesia. A small race cut to divert a small river around a waterfall (presumably to allow the alluvium in the plunge pool to be extracted). Judging by the size of trees in the diversion channel, it was several hundred years old!
In the area where I live, there are mountains and valleys with ancient mines from the Roman era. What is the best way to work?
Very first step is to secure mineral rights on the area. If you dont have the right to mine what you find, your efforts will be wasted.
Is there a way to tell how deep the alluvial diggings were?
You can get a rough idea by estimating the volume of each dump in cubic metres and multiplying by 2. Most historical alluvial shafts that I have seen in good condition are about 1m x 0.5m in plan so they would generate about 1 cubic metre of mullock for every 2m down. It's a pretty rough estimate, but saves a lot of digging!
Yes, dowsing with the modern light weight ball bearing dowsing rod while using physics will accurately decipher all edges, exact center, depth buried and angle of deposition, and most important GRADING. Read the book The Art of Dowsing - Separating Science from Superstition for learning all the physics involved and how to use it in dowsing.
Interesting !
Thanks!
Cheers👍
thanks sir, wow
Glad you found the info useful.
Good One Mr Nick, in Laos, we just follow the Vietnamese Excavators to the aluvial pits? No problem> One suggestion on your Video Production> More Dirt Bikes, please :)
555 Yep, you can see those excavator pits from space!
:)
Aren't they claimed? You get shot for doing that here in Arizona lol
AWESOME" SHOW of FINE GOLD SLUGS! Cheers" from -7c Idaho USA - newsub'
That's the stuff!
too good and lick
Thanks. Much appreciated.